なくてもいいdon't have to
なくてもいい says it is fine not to do something: "don't have to". It takes a duty away. It forbids nothing.
You don't have to take your shoes off here.
You do not have to hurry that much.
How to form it
Verb in the ない-form, with ない changed to なくて + もいい
行かない → 行かなくてもいい, 食べない → 食べなくてもいい, しない → しなくてもいい, 来ない → 来なくてもいい. Polite いいです. In conversation the も often drops: 行かなくていい.
With a noun or an adjective
Noun + じゃなくてもいい ／ い-adjective 〜くなくてもいい
"Doesn't have to be": 今日じゃなくてもいい, 新しくなくてもいい. A な-adjective works like a noun.
Saying it isn't needed
You say it when someone thinks they have to do something and they don't.
You do not have to bring lunch.
You do not have to do all of the homework.
With 全部 it is normally "not all of it": some is still expected. 全部は makes that certain.
Tomorrow is a day off, so I don't have to get up early.
With よ it is often a kindness: no need to worry, to hurry, to go to any trouble.
You don't have to worry.
You don't have to force yourself to eat it.
Asking: なくてもいいですか
This checks whether something is required.
Is it okay not to fill in this field?
Yes, you can leave it blank.
English more often asks "Do I have to fill this in?" and answers "No". The Japanese asks whether leaving it is fine, so the answer is はい.
It is also the no to "do I have to?", なければなりませんか.
Do I have to come tomorrow too?
No, you don't have to.
May, must not, don't have to
Three forms that go together. Word for word, they say:
You may use a dictionary.
"Even if you use one, it's fine."
You must not use a dictionary.
"If you use one, it's no good."
You don't have to use a dictionary.
"Even if you don't use one, it's fine."
も comes before いい, and は before いけない.
In conversation: なくていい
You don't have to wash the dishes.
You don't need to worry about it.
大丈夫 often takes the place of いい.
You don't need to take an umbrella.
After a noun or an adjective
It doesn't have to be today. Tomorrow is fine too.
The computer doesn't have to be new.
Close neighbours
ないほうがいいN5
Advice: "better not to". なくてもいい only says there is no need.
It would be better not to go today.
"I don't mind if you don't." A little stiffer than なくてもいい.
You do not have to reply today; that will not be a problem.
てもN4
Without いい after it, なくても is "even if you don't".
I can understand it even without using a dictionary.
Check yourself
1What does this mean?
明日は
Choose an answer to see why.
2The teacher's answer is that there is no need. Which one fits?
A：レポートは
Choose an answer to see why.
More sentences
You do not have to wear a uniform today.
You do not have to memorize all of these words.
You do not have to come early tomorrow.
You don't have to take the medicine any more.
Is it okay not to copy this document?